64141-11-3Relevant academic research and scientific papers
Evaluation of Cyclic Amides as Activating Groups in N-C Bond Cross-Coupling: Discovery of N-Acyl-δ-valerolactams as Effective Twisted Amide Precursors for Cross-Coupling Reactions
Bisz, Elwira,Chen, Hao,Dziuk, B?a?ej,Ejsmont, Krzysztof,Lalancette, Roger,Pyle, Daniel J.,Rahman, Md. Mahbubur,Szostak, Michal,Szostak, Roman,Wang, Qi
, p. 10455 - 10466 (2021/07/31)
The development of efficient methods for facilitating N-C(O) bond activation in amides is an important objective in organic synthesis that permits the manipulation of the traditionally unreactive amide bonds. Herein, we report a comparative evaluation of a series of cyclic amides as activating groups in amide N-C(O) bond cross-coupling. Evaluation of N-acyl-imides, N-acyl-lactams, and N-acyl-oxazolidinones bearing five- and six-membered rings using Pd(II)-NHC and Pd-phosphine systems reveals the relative reactivity order of N-activating groups in Suzuki-Miyaura cross-coupling. The reactivity of activated phenolic esters and thioesters is evaluated for comparison in O-C(O) and S-C(O) cross-coupling under the same reaction conditions. Most notably, the study reveals N-acyl-δ-valerolactams as a highly effective class of mono-N-acyl-activated amide precursors in cross-coupling. The X-ray structure of the model N-acyl-δ-valerolactam is characterized by an additive Winkler-Dunitz distortion parameter ?(τ+χN) of 54.0°, placing this amide in a medium distortion range of twisted amides. Computational studies provide insight into the structural and energetic parameters of the amide bond, including amidic resonance, N/O-protonation aptitude, and the rotational barrier around the N-C(O) axis. This class of N-acyl-lactams will be a valuable addition to the growing portfolio of amide electrophiles for cross-coupling reactions by acyl-metal intermediates.
Highly efficient synthesis of aryl ketones by PEPPSI-palladium catalyzed acylative Suzuki coupling of amides with diarylborinic acids
Wang, Chen,Huang, Lingyun,Wang, Fengze,Zou, Gang
supporting information, p. 2299 - 2301 (2018/05/16)
An improved acylative cross-coupling of various N-methyl-N-tosyl amides with diarylborinic acids for synthesis of aryl ketones is developed. In most cases, aryl ketones could be obtained in excellent yields by using 1 mol% 2,6-diisopropylphenylimidazolylidene and 3-chloropyridine co-supported palladium chloride as catalyst in the presence of 3 equiv. K2CO3 as base in refluxing THF. The readily prepared and cost-effective substrates, N-methyl-N-tosylamides and diarylborinic acids, and the commercially available catalyst system promise a practical and efficient access to aryl ketones.
Pd/C in Propylene Carbonate: A Sustainable Catalyst–Solvent System for the Carbonylative Suzuki–Miyaura Cross-Coupling Using N-Formylsaccharin as a CO Surrogate
Gautam, Prashant,Gupta, Rashi,Bhanage, Bhalchandra M.
, p. 3431 - 3437 (2017/07/04)
This work documents the first Pd/C-catalyzed carbonylative Suzuki–Miyaura cross-coupling of aryl iodides with N-formylsaccharin as a CO surrogate. In contrast to previous reaction protocols, which make use of toxic and hazardous solvents, the reaction could be advantageously performed in propylene carbonate as an environmentally benign and sustainable polar aprotic solvent. A range of biaryl ketones, including (4-methoxyphenyl)(3,4,5-trimethoxyphenyl)methanone, an antineoplastic belonging to the phenstatin family, could be synthesized under cocatalyst-free, additive-free and ligand-free conditions. The Pd/C could be recycled up to five times under CO surrogacy with only a marginal decrease in catalytic activity. The reaction could also be scaled up to gram-scale syntheses.
Palladium-Catalyzed Room-Temperature Acylative Suzuki Coupling of High-Order Aryl Borons with Carboxylic Acids
Si, Shufen,Wang, Chen,Zhang, Nan,Zou, Gang
, p. 4364 - 4370 (2016/06/09)
This note describes a dimethyl dicarbonate-assisted, Pd(OAc)2/PPh3-catalyzed acylative Suzuki coupling of carboxylic acids with diarylborinic acids or tetraarylboronates for practical and efficient synthesis of sterically undemanding aryl ketones at room temperature. More than just cost-effective alternatives to aryl boronic acids, diarylborinic acids and tetraarylboronates displayed higher reactivity in the acylative Suzuki coupling. A variety of alkyl aryl ketones, including those bearing a hydroxy, bromo, or carbonyl group, could be readily obtained in modest to excellent yields.
Palladium-catalyzed acylative cross-coupling of amides with diarylborinic acids and sodium tetraarylborates
Li, Xijing,Zou, Gang
, p. 136 - 145 (2015/07/27)
Abstract A general and efficient acylative Suzuki coupling of active amides with diarylborinic acids has been achieved by using 1 mol% Pd(PCy3)2Cl2/0.6 mol% PCy3 as catalyst system taking advantage of modifiable reactivities of acyl-nitrogen bonds of amides. Both electronic and steric influences from either aryl or acyl counterparts on the coupling proved to be negligible or small. A variety of aryl ketones including sterically hindered ones could be synthesized by the coupling of diarylborinic acids in good to excellent yields. Sodium tetraarylborates could also be used as high atom-economy aryl source in the palladium-catalyzed cross-coupling with active amides.
Chemoselective synthesis of ketones and ketimines by addition of organometallic reagents to secondary amides
Bechara, William S.,Pelletier, Guillaume,Charette, Andre B.
experimental part, p. 228 - 234 (2012/06/01)
The development of efficient and selective transformations is crucial in synthetic chemistry as it opens new possibilities in the total synthesis of complex molecules. Applying such reactions to the synthesis of ketones is of great importance, as this motif serves as a synthetic handle for the elaboration of numerous organic functionalities. In this context, we report a general and chemoselective method based on an activation/addition sequence on secondary amides allowing the controlled isolation of structurally diverse ketones and ketimines. The generation of a highly electrophilic imidoyl triflate intermediate was found to be pivotal in the observed exceptional functional group tolerance, allowing the facile addition of readily available Grignard and diorganozinc reagents to amides, and avoiding commonly observed over-addition or reduction side reactions. The methodology has been applied to the formal synthesis of analogues of the antineoplastic agent Bexarotene and to the rapid and efficient synthesis of unsymmetrical diketones in a one-pot procedure. Macmillan Publishers Limited. All rights reserved.
Mobilizing Cu(I) for carbon-carbon bond forming catalysis in the presence of thiolate. Chemical mimicking of metallothioneins
Zhang, Zhihui,Lindale, Matthew G.,Liebeskind, Lanny S.
supporting information; experimental part, p. 6403 - 6410 (2011/06/19)
Copper(I) is rendered catalytically viable in the presence of thiolate by the design of a small molecule chemical analogue of the metallothionein system in which an N-O reactant serves the same conceptual purpose of the S-S reactant of the biological system.
Ligand-free Pd-catalyzed carbonylative cross-coupling reactions under atmospheric pressure of carbon monoxide: Synthesis of aryl ketones and heteroaromatic ketones
Li, Hongling,Yang, Min,Qi, Yanxing,Xue, Jijun
supporting information; experimental part, p. 2662 - 2667 (2011/06/25)
The carbonylative Suzuki cross-coupling reactions of boronic acids with aryl iodides catalyzed by Pd2(dba)3 as a ligand-free catalyst under atmospheric pressure of carbon monoxide has been firstly developed. Under mild reaction conditions, a broad range of aryl/heteroaryl iodides and aryl/heteroaryl boronic acids were selectively coupled to afford the corresponding diaryl ketones in good to excellent yields at low catalyst loadings (0.05 to 2 mol-%). Moreover, the catalyst can also be recycled. The carbonylative Suzuki cross-coupling reactions of boronic acids with aryl iodides catalyzed by Pd2(dba)3 as a ligand-free catalyst under an atmosphere of carbon monoxide has been developed. A broad range of aryl/heteroaryl iodides and aryl/heteroaryl boronic acids were selectively coupled to afford the corresponding diaryl ketones in good to excellent yields. The catalyst can also be recycled.
A phosphine-free carbonylative cross-coupling reaction of aryl iodides with arylboronic acids catalyzed by immobilization of palladium in MCM-41
Cai, Mingzhong,Peng, Jian,Hao, Wenyan,Ding, Guodong
experimental part, p. 190 - 196 (2011/03/20)
The phosphine-free heterogeneous carbonylative cross-coupling of aryl iodides with arylboronic acids under an atmospheric pressure of carbon monoxide was achieved in anisole at 80 °C in the presence of a 3-(2-aminoethylamino) propyl-functionalized MCM-41-immobilized palladium(ii) complex [MCM-41-2N-Pd(ii)], yielding a variety of unsymmetrical biaryl ketones in good to high yield. This heterogeneous palladium catalyst exhibited higher activity and selectivity than PdCl2(PPh3)2, can be recovered and recycled by a simple filtration of the reaction solution, and used for at least 10 consecutive trials without any decrease in activity. Our system not only avoids the use of phosphine ligands, but also solves the basic problem of palladium catalyst recovery and reuse.
Diaryl ketone synthesis by [RuHCl(CO)(PPh3)3]- catalyzed coupling reaction of arylboronic acids with aryl aldehydes
Fukuyama, Takahide,Okamoto, Hiromi,Ryu, Ilhyong
, p. 1453 - 1455 (2013/05/22)
[RuHCl(CO)(PPh3)3] was found to be an efficient catalyst for the coupling reaction of arylboronic acids with aryl aldehydes. The reaction proceeded smoothly in the presence of K2CO3 and H2O to give diaryl ketones in good yields. Diaryl ketones were obtained from primarily formed alcohols via Rucatalyzed transfer hydrogenation reaction.
